Wood has been widely used for generations as an optimum material for building and for furniture because of many advantages such as beauty, an appearance of quality, workability, availability and recyclability. A continual problem has been the joining of wood members to withstand stress. Nails and metal fittings have been used for joining columns or girders in a house, and bolts, lug screws, and drift pins have been used for joining trusses in a large building. However in order to join members without decreasing strength, a number of joining materials or large metal fittings are required. Resulting problems are cost increase and appearance impairment.
Joining of wood has been carried out by adherence methods, but this has been limited to small members carrying small stresses as in the construction of furniture. For the utilization of adherence joining in large wooden buildings, adhesives of greater strength and fire resistance and the development of simple, reliable joining techniques are desirable.